Zabbix templates monitor zabbix internal processes by "average busy time" like zabbix[process,housekeeper,busytime]. This works good for all other zabbix processes but not for housekeeper that switch between 100% busy when working and 0% when idle.

Best solution would be item that records last housekeeping duration but a cheaper workaround is counting "housekeeper duration" by calculated item (attached).

This would make more understandable graphs, easier to see when storage degraded too much. With current disk prices there will be more of us who can't afford upgrades.